Compilare: user.cpp: In function ‘void CountingSort(unsigned int*, unsigned int*, unsigned int)’: user.cpp:11:62: warning: operation on ‘i’ may be undefined [-Wsequence-point] for(; i != 0x100; index[++i] = index[~-i] + frequence[~-i]); ^ user.cpp:11:62: warning: operation on ‘i’ may be undefined [-Wsequence-point] user.cpp: At global scope: user.cpp:18:37: warning: always_inline function might not be inlinable [-Wattributes] __attribute__((always_inline)) void itoa(unsigned int x) ^ user.cpp:5:37: warning: always_inline function might not be inlinable [-Wattributes] __attribute__((always_inline)) void CountingSort(unsigned int A[], unsigned int B[], unsigned int digit) ^ user.cpp: In function ‘int main()’: user.cpp:42:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("radixsort.in", "r", stdin); ^ user.cpp:43:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("radixsort.out", "w", stdout); ^ user.cpp:45:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d", &N, &A, &B, &C); ^